i have no idea how these things even work
but i will say i'm a little more subtle on my skeptisism these days
many times i have seen these people on tv with their deviding rods
and many times i have laughed,untill one day,a utility worker showed up on the job
looking for the underground utilities,and had forgotten to bring the proper equiptment for locating it
this guy says to me don't tell anyone i did this,he walkes over to his truck and pulls out a pair of deviding rods
you've got to be kidding me i says,now i'm thinkin this guy has some cards missing,i literally was laughing out loud
what are you going to do with those i says,well long story short,this guy located the utilities with no problem,then let
me locate them,and i'm a skeptic no longer!
i still laugh at the plumb bob over the map deal-just not out loud!
bottom line some one would have to prove these things to me before i bit!
seems to me that these long range locaters would have a huge problem with interferance?
although tabdog seems to have this problem all taken care of